[quote=@TheUnknowable]
[@Burning Kitty]We could just say that it had a shuttle, something small but fancy enough to work as a diplomatic shuttle.  Preferably something without a hyperdrive.
[/quote]

The whole point of showing Vader inVadering :D the diplomatic ship was to prove diplomatic ships mean nothing to the Empire or least Vader.

Could just have Leia's ship get to Tatoonie faster than Vader's ship. The shuttle that takes Leia to the surface could have returned so Vader doesn't look on the planet for a while.